1. Field of the Invention
The present invention relates to a lighting device, an image capturing system, and a lighting control method.
2. Description of the Related Art
When capturing an image of, i.e. photographing an object using a camera, there are many cases where the object is photographed using not only natural light but also light emitted from a lighting device such as a fluorescent lamp or LEDs. However, when photographing the object using the light emitted from the lighting device, there are cases where a flicker noise is generated in a photographed image due to flicker of the emission light by using an AC power supply as the power supply. Thus, among conventional image capturing apparatuses, there are apparatuses that eliminate flicker by integrating an image while changing shutter speed or a gain value (for example, Japanese Laid-open Patent Publication No. 7-298130) or by detecting a flicker frequency and performing control of the shutter speed to be higher than the detected flicker frequency (for example, Japanese Laid-open Patent Publication No. 9-284634).
Generally, in a lighting device, the amount of light is adjusted such that the light is emitted with a brightness level preferred by a user using the light emitted from the lighting device. However, the brightness level at this amount of the light may be different from a brightness level that is appropriate to a photographing process performed by a camera. Accordingly, in the case of photographing an image by a camera using light emitted from a lighting device, acquisition of an appropriate image is apt to become difficult. Consequently, it is quite difficult to acquire a function as a lighting device where light is emitted with a brightness level preferred by the user, while acquiring an appropriate image where light is emitted with a brightness level that is appropriate to the photographing process performed in the camera.